Sandwiched R\'enyi Divergence Satisfies Data Processing Inequality

Understand

Sandwiched (quantum) $\alpha$-R\'enyi divergence has been recently defined in the independent works of Wilde et al.

• (arXiv:1306.1586) and M\"uller-Lennert et al (arXiv:1306.3142v1).
• This new quantum divergence has already found applications in quantum information theory.
• Here we further investigate properties of this new quantum divergence.